Laser level

ABSTRACT

A laser level disposable on a reference surface includes a housing, a pendulum pivotably connected to the housing, a first laser diode disposed on the pendulum for emitting a first laser beam along a first path, and a lens disposed on the pendulum in the first path for converting the first laser beam into a first planar beam, the first planar beam forming a line on the reference surface.

FIELD OF THE INVENTION

[0001] This invention relates generally to laser instruments andspecifically to laser levels.

BACKGROUND OF THE INVENTION

[0002] Laser levels have been used in construction for many years. Theytypically seek to produce a plane of light for a reference forconstruction projects. Laser levels have been used for large scaleconstruction projects like commercial excavating, laying foundations,and installing drop ceilings. Laser levels save considerable time duringinitial layout of a construction job compared to other tools such asbeam levels, chalk lines, or torpedo levels. Some examples of jobs wherelaser levels would be useful include laying tile, mounting cabinets,installing counter tops, and building outdoor decks.

[0003] It is an object of the present invention to provide a laser levelthat is inexpensive and usable by the general public.

SUMMARY OF THE INVENTION

[0004] In accordance with the present invention, an improved laser levelis employed. The laser level disposable on a reference surface includesa housing, a pendulum pivotably connected to the housing, a first laserdiode disposed on the pendulum for emitting a first laser beam along afirst path, and a lens disposed on the pendulum in the first path forconverting the first laser beam into a first planar beam, the firstplanar beam forming a line on the reference surface.

[0005] Additional features and benefits of the present invention aredescribed, and will be apparent from, the accompanying drawings and thedetailed description below.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The accompanying drawings illustrate preferred embodiments of theinvention according to the practical application of the principlesthereof, and in which:

[0007]FIG. 1 is a perspective view of a first embodiment of a laserlevel according to the invention;

[0008]FIG. 2 is a cross-sectional view of the laser level of FIG. 1;

[0009]FIG. 3 illustrates different laser diode/lens arrangements, whereFIG. 3A is a partial cross-sectional front view of an arrangement, andFIGS. 3B-3E are top views of alternate arrangements;

[0010]FIG. 4 illustrates another laser diode/lens arrangement, whereFIG. 4A is a partial cross-sectional top view of such arrangement, FIG.4B is an augmented view of FIG. 4A; FIG. 4C is a partial cross-sectionalview along line IV-IV of FIG. 4B, FIG. 4D is an augmented top drawing ofthe lens in FIG. 4A, FIG. 4E is an augmented top drawing of a firstalternate lens, FIG. 4F is a front view of a second alternate lens, andFIG. 4G is a cross-sectional view along line G-G of FIG. 4F;

[0011]FIG. 5 illustrates the laser level being used with a target, whereFIGS. 5A-5B are front and top views, respectively;

[0012]FIG. 6 illustrates the target of FIG. 5, where FIGS. 6A-6B showthe target independently and with the laser level, respectively;

[0013]FIG. 7 is a wall hanging assembly for the laser level;

[0014]FIG. 8 is a partial cross-section of a second embodiment of thelaser level, where FIGS. 8A-8B show the laser level in vertical andinclined positions, respectively;

[0015]FIG. 9 illustrates a pendulum lock mechanism according to theinvention;

[0016]FIG. 10 illustrates a third embodiment of the laser level, whereFIGS. 10A-10C show a laser assembly disposed on right, top and leftpositions, respectively, and FIG. 10D is an exploded diagram of thelaser level;

[0017]FIG. 11 is a block diagram of the components of the laser level;

[0018]FIG. 12 is an alternate block diagram of the components of thelaser level;

[0019]FIG. 13 illustrates a fourth embodiment of the laser level, whereFIGS. 13A-13B are perspective and cross-sectional views of the laserlevel, respectively; and

[0020]FIG. 14 illustrates another wall hanging assembly for the laserlevel.

DETAILED DESCRIPTION

[0021] The invention is now described with reference to the accompanyingfigures, wherein like numerals designate like parts. Referring to FIGS.1-2, a laser level 10 may have a housing 11. The housing 11 may have atop portion 11T and a bottom portion 11B. The housing may also have ahole 12 extending through the housing 11. The hole 12 preferably extendsthrough the top portion 11T. The perimeter of the hole 12 may be definedby an inner wall 11I.

[0022] The top portion 11T may carry a pendulum assembly 30. Preferably,the pendulum assembly 30 has a main body 31, which may be made of metalor plastic. Main body 31 may be disposed on a knife edge 11IK. Knifeedge 11IK may be connected to and/or supported by inner wall 11I.Alternatively, knife edge 11IK may be connected to and/or supported byhousing 11. Persons skilled in the art will recognize that pendulumassembly 30 may be supported by means other than knife edge 11IK, suchas a pin, bearing, point or other pendulous means.

[0023] The main body 31 may carry at least one laser assembly 40 andpreferably two laser assemblies 40 disposed left and right of the knifeedge 11IK. Persons skilled in the art will recognize that a laserassembly 40 may disposed above knife edge 11IK. Persons skilled in theart will also recognize that the laser assemblies 40 will emit laserbeams. Accordingly, it is preferable to provide housing 11 with windows13 to allow the laser beams to exit from housing 11.

[0024] Persons skilled in the art will recognize that such arrangementwill provide a self-leveling pendulum assembly that will emitsubstantially horizontal laser beams (and a substantially vertical laserbeam if a laser assembly 40 is disposed above knife edge 11IK and isdirected upwardly) when laser level 10 is disposed against a wall.Persons skilled in the art will also recognize that it is preferable toallow laser assembly 40 to be angularly adjusted along a vertical planerelative to main body 31, to ensure that the projected laser beam issubstantially horizontal when the main body 31 is at its stationaryposition.

[0025] A possible adjustment arrangement is shown in FIG. 8A, wherelaser assembly 40 has a barrel 41 carrying the laser diode and lens(es)(not shown). Barrel 41 may be disposed on a pin 38 supported by mainbody 31. A spring 39 preferably disposed between barrel 41 and main body31 may bias barrel 40 upwardly against set screw 37. Set screw 37 ispreferably disposed on main body 31 and contacts barrel 41 to stoprotation of barrel 41 about pin 38, and set the position of barrel 41(and thus of laser assembly 40). Persons skilled in the art willrecognize that the set screw 37 is preferably locked in place using alocking compound such as Loc-Tite.

[0026] A second possible adjustment arrangement is also shown in FIG.8A, where like numerals refer to like parts. In this arrangement, barrel41 may be disposed against a protrusion 31P by main body 31. A spring39′ preferably disposed between barrel 41 and main body 31 may biasbarrel 40 downwardly against set screw 37. Set screw 37 is preferablydisposed on main body 31 and contacts barrel 41 to stop rotation ofbarrel 41 about protrusion 31P, and set the position of barrel 41 (andthus of laser assembly 40). Persons skilled in the art will recognizethat the set screw 37 is preferably locked in place using a lockingcompound such as Loc-Tite.

[0027] Referring to FIGS. 1-2, main body 31 may also have weights 33 toprovide a lower center of gravity, and enhance the performance of thependulum assembly 30. In addition, main body 31 may have at least oneadjustment screw 33A to adjust the center of gravity of pendulumassembly 30, as necessary.

[0028] Main body 31 may also have a plaque 33M, made of magneticmaterial, ferrous material or non-ferrous conductive material, such aszinc or copper. Plaque 33M preferably is aligned with at least onemagnet (and preferably two magnets) disposed in housing 11, e.g., on theinside of the front and rear walls of housing 11, for providing adamping action on pendulum assembly 30. Basically, eddie currents aregenerated within plaque 33M, as the plaque moves and interacts with themagnetic field supplied by the magnet(s).

[0029] Persons skilled in the art shall recognize that pendulum assembly30 is preferably wholly contained within housing 11. However, thependulum assembly 30 may be at least partly, if not completely, disposedoutside of housing 11.

[0030] Persons skilled in the art shall recognize that a dampingmechanism for damping the motion of pendulum assembly 30 may beprovided. Persons skilled in the art are directed to the dampingmechanism disclosed in U.S. Pat. No. 5,144,487, which is whollyincorporated by reference herein, as well as to its equivalents.

[0031] The bottom portion 11B of housing 11 may carry a battery 50 forpowering the laser assemblies 40. In addition, the bottom portion 11Bmay carry a stud sensor circuit 20. The circuitry of the stud sensorcircuit 20 is not illustrated herein. Persons skilled in the art arereferred to U.S. Pat. Nos. 4,099,118 and 4,464,622, which are whollyincorporated herein by reference.

[0032] As is well known in the art, the stud sensor circuit 20 mayinclude an on/off actuator or switch 21, which can be a push-button typeactuator. Stud sensor circuit 20 may also include light emitting diodes22 to display the location of a stud.

[0033] It is preferable to align the sensors within stud sensor circuit20 with the center of hole 12, so that the center of hole 12 indicatesthe location of the stud.

[0034] Persons skilled in the art should recognize that detectorcircuits other than stud sensor circuit 20 may be provided in laserlevel 10. Preferably, these detector circuits can detect featuresunderneath a surface, such as a wall or floor. These features mayinclude pipes or wires. Circuits for pipe and wire detectors, as well asother detector circuits, are well known in the art.

[0035] The housing 11 may be formed from a hard impact resistant,preferably moldable material such as a hard thermoplastic material suchas ABS or polystyrene. It is preferable to provide a grip 14 on bottomportion 11B. Grip 14 may be made of a soft or low durometerthermoplastic elastomer. In addition, grip 14 can be formed from any ofthe so-called “soft-touch” elastomer materials, such as those sold underthe tradenames “Santoprene”, “Kraton” and “Monprene,” and are preferablyadhered or overmolded to the housing 11.

[0036] Referring to FIGS. 2-3, laser assemblies 40 are disposed on mainbody 31. Laser assembly 40 may include a substantially cylindricalbarrel 41, which may be adjustably connected to main body 31, laserdiode 42 disposed in barrel 41, and a line lens 43 disposed in barrel41. Persons skilled in the art will recognize that in the preferredembodiment, adjusting barrel 41 will result in moving laser diode 42 andline lens 43. In addition, persons skilled in the art will recognizethat a collimating lens may be disposed between laser diode 42 and linelens 43.

[0037] Preferably, line lens 43 converts the laser beam exiting laserdiode 42 into a planar beam. Line lens 43 may have different shapes toaccomplish such purpose. For example, as shown in FIGS. 3B-3D, linelenses 43A, 43B, 43C may have a substantially circular cross-section,half-circle cross-section or quarter-circle cross-section, respectively.Alternatively, line lens 43D may have a compound cross-section, whichincludes a rectangle connected to a quarter-circle.

[0038] Accordingly, when laser level 10 is disposed against a wall,laser assembly 40 will preferably emit a laser plane that contacts thewall, forming a laser line on the wall. Persons skilled in the art willrecognize that it is preferable to orient the laser assemblies 40 insuch manner so that at least a portion of the laser plane will contactthe wall. In addition, persons skilled in the art will recognize thatproviding laser assemblies 40 on the pendulum assembly 30 discussedabove will preferably result in laser level 10 projecting substantiallyhorizontal laser lines against the wall (and a substantially verticallaser beam if a laser assembly 40 is disposed above knife edge 11IK andis directed upwardly).

[0039] Persons skilled in the art will recognize that line lenses 43B,43C, 43C will limit the angle of plane divergence. In other words, if ahorizontal line HL is 0°, the plane exiting from line lens 43A mayextend from, for example, −30° to 30°, providing an angle of planedivergence DA of 60°. On the other hand, the plane exiting from linelenses 43B, 43C, 43D may extend from, for example, 0° to 30°, providingan angle of plane divergence DA of 30°. This provides for a moreefficient use of the laser beam, directing more energy towards the wall,rather than away from the wall. Persons skilled in the art willrecognize that directing more energy towards the wall is preferable asit would result in a brighter laser line on the wall.

[0040] A preferred laser assembly 40′ is shown in FIG. 4, where likenumerals refer to like parts. Such laser assembly 40′ has a collimatinglens 44 disposed in the laser beam path, as well as a line lens 45disposed in the laser beam path after the collimating lens 44. Line lens45 is preferably a prismatic lens that includes at least two cylindricallens forms with significantly different focal distances to generate atleast two superimposed laser planes with different divergence angles andtrajectories.

[0041] With such arrangement, when laser assembly 40′ is placed near awall W, two or more lines are projected onto wall W. At least one ofthese lines (L1) may be directed to strike the wall W at a shortdistance along the wall surface, while another of these lines (L2) maybe directed to strike the wall W at a longer distance. This preferablyincreases the overall length and/or apparent brightness of the laserline shown on the wall W. Lines L1, L2 may partially overlap or may beseparated to further increase the length of the resulting laser line onwall W.

[0042] As mentioned above, line lens 45 may have two portions. Oneportion has a long focal distance for generating the high density lineL2, i.e., having a small divergence angle. The brightness of line L2along wall W will depend of the divergence angle H, as the smaller thedivergence angle, the brighter the line at a given distance.

[0043] But a small divergence angle H will result in a laser line gap onthe wall W between the laser assembly 40′ (and thus laser level 10) andthe beginning of line L2. Accordingly, it is preferable to provide linelens 45 with a second portion with a short focal distance for generatinga line L1 with lower density than the line L2, and thus having a largerdivergence angle L. The larger divergence angle L will create a lowdensity line L1 that will contact wall W closer to the laser assembly40′, thus reducing the laser line gap left by line L2.

[0044] Persons skilled in the art will recognize that the first andsecond portions will have a first and second radii R1, R2, respectively.Preferably, radius R1 is substantially larger than radius R2. Personsskilled in the art will know how to select the appropriate radii, asthey must be selected based on the distance from the wall W to laserassembly 40′, the desired length of laser line gap to fill up, etc.

[0045] Persons skilled in the art will recognize that the laser beam LBcreated by the collimating lens 42 has a generally oval cross-section.The use of the long axis of the oval allows easier positioning of thebeam to pass the two portions of line lens 45. It is desirable to orientthe laser beam LB so that the short axis of the oval is aligned in theaxis of the line lens 45 that offers no or minimal magnification.Accordingly, the short axis preferably provides the width of laser linesL1, L2. Persons skilled in the art will recognize that a narrower widthis preferable as it increases accuracy and intensity of the laser lines.In a preferred embodiment, the short and long axes are about 3 mm andabout 7 mm respectively.

[0046] Persons skilled in the art will also recognize that the abovediscussion is preferably applicable to line lens 45, as well as toalternate line lens 45′ (FIGS. 4E-4G), except that the second portionwith R2 is concave, i.e., extending into the lens, rather convex, i.e.,extending out of the lens. In the embodiment of FIGS. 4F-4G, line lens45′ has radii R1, R2 of about 12.70 mm and about 0.75 mm, respectively.

[0047] It may also be preferable to provide line lens 45′ withprotrusions 45P to engage barrel 41.

[0048] Furthermore, it is preferable to provide a means of line lens 45′to delimit the width of the laser plane generated by laser assembly 40′.One such means is by providing a screen 45S on the wall 45F closest tolaser diode 42. With such screen 45S, the shape or width of the emittedlaser plane can be controlled. For example, screen 45S can define anunscreened line through which the laser beam is transmitted.

[0049] In the present embodiment, screen 45S is basically a texturemolded onto wall 45F. However, persons skilled in the art will recognizethat screen 45S can be an opaque material, such as paint, metal orfabric, which is disposed on or adjacent to line lens 45′. Furthermore,screen 45S could be disposed on or adjacent to wall 45R, or within linelens 45′. Alternatively, screen 45S can be disposed ahead of lens 44.

[0050] Referring to FIG. 5, regardless of the type of line lens used, itis likely that the laser line will fade as it gets farther from laserlevel 10. As shown in FIG. 5B, the emitted laser plane LP still has acomponent that does not contact the wall W. This component will form alaser line when it contacts another surface.

[0051] Accordingly, it is preferable to provide a surface that canintersect this component of the laser plane LP. This surface can beprovided on a movable target 60. Target 60 may have a main body 61, anda cylinder 62 disposed on the body 61. Preferably, the inside ofcylinder 62 is carved out, forming a hollow cone 62C ending in a centralbore 63. Target 60 may have cross-hair indicia, such as grooves 65 orribs, intersecting at the center of bore 63.

[0052] Persons skilled in the art will recognize that target 60, mainbody 61 and/or cylinder 62 may be made of a translucent material tofacilitate location of a mark. This could facilitate placing the laserlevel 10 on a specifically desired location.

[0053] A ramp 64 may be provided on cylinder 62. Preferably the ramp 64has some reflective material. (Alternatively, textured areas can bedisposed on cylinder 62 or ramp 64 to enhance the visibility of thelaser line.) Accordingly, the user can disposed the laser level 10 onwall W and move target 60 until ramp 64 is aligned with the laser line.

[0054] The user can then use a pencil to mark the center of target 60.Alternatively, the user can push a pin 66P or expanding mandrel 66Mthrough bore 63 to maintain the target 60 in place. Persons skilled inthe art will recognize that an expanding mandrel has at least two metalstrips along its longitudinal axis meeting at a front tip. The mandrelis inserted into a pre-drilled hole. The steel strips can be thenexpanded within the hole in order to fix the mandrel.

[0055] Persons skilled in the art will recognize that target 60 may beremovably disposed in hole 12 of laser level 10. Thus, laser level 10provides on-board storage for target 60. To this end, it is preferableto provide target 60 with detent protrusions 67, which engage the laserlevel 10.

[0056] Persons skilled in the art will recognize that, if the center ofhole 12 is aligned with the horizontal lines emitted by the laserassemblies 40, the bore 63 of target 60 will be placed at theintersection of the vertical centerline of laser level 10 with thehorizontal lines. In addition, the laser level 10 may be hung by pushinga pin through bore 63 and nesting laser level 10 unto target 60.

[0057] It may also be preferable to provide a hanger assembly 70 forlaser level 10. Hanger assembly 70 may have a main body 71 with acentral hole 72 for receiving the head of a nail hammered into a wall.Main body 71 may be made of a translucent material to facilitatelocation of a mark or nail.

[0058] Hanger assembly 70 may also have a ramp 73, as cross-hairindicia, such as grooves 74 or ribs, intersecting at the center of hole72. Textured areas can be disposed on main body 71 or ramp 73 to enhancethe visibility of the laser line.

[0059] Hanger assembly 70 may be removably disposed in hole 12 of laserlevel 10. To this end, it is preferable to provide hanger assembly 70with detent protrusions 77, which engage the laser level 10.

[0060] Persons skilled in the art will recognize that housing 11 may beprovided with holes for receiving nail heads or screw heads, for hanginglaser level 10 thereon.

[0061] It may also be preferable to provide a separable hanger assembly90 for laser level 10. Hanger assembly 90 may have a main body 91, amagnet 93 disposed on the main body 91, and a ramp 92. Main body 91 mayalso have cross-hair indicia, such as grooves or ribs, intersecting atits center. Hanger assembly 90 may be removably disposed in hole 12 oflaser level 10. To this end, it is preferable to provide hanger assembly90 with detent protrusions 94, which engage the laser level 10.

[0062] Main body 91 may magnetically engage another assembly, such aswall assembly 95, pin assembly 96 and/or mandrel assembly 97. Wallassembly 95 preferably has a body 95B, a magnetically-responsive metalplate 95 MP supported by body 95B, and a hole 95H. Basically, the usercan dispose wall assembly 95 on a nail or screw on a wall. The user canthen dispose main body 91 unto wall assembly 95, which will staytogether because of the magnet/metal plate combination.

[0063] Pin assembly 96 preferably has a body 96B, amagnetically-responsive metal plate 96 MP supported by body 96B, and apin 96P. Basically, the user can dispose pin assembly 96 unto a wall.The user can then dispose main body 91 unto pin assembly 96, which willstay together because of the magnet/metal plate combination.

[0064] Mandrel assembly 97 preferably has a body 97B, amagnetically-responsive metal plate 97 MP supported by body 97B, and amandrel 97M. Basically, the user can dispose mandrel assembly 97 withina pre-drilled hole on a wall. The user can then dispose main body 91unto mandrel assembly 97, which will stay together because of themagnet/metal plate combination.

[0065] Persons skilled in the art will recognize that it is alsopreferable to provide a rib 98 on main body 91 that receives wallassembly 95, pin assembly 96 and/or mandrel assembly 97, or a portionthereof. Preferably, the rib 98 is designed so that, when main body 91is disposed on wall assembly 95, pin assembly 96 and/or mandrel assembly97, the main body 91 is centered relative to the opposite assembly. Rib98 may also support main body 91 (and thus laser level 10). Personsskilled in the art will recognize that the rib 98 may be disposed onwall assembly 95, pin assembly 96 and/or mandrel assembly 97.Alternatively, rib 98 may be received within a slot or groove of wallassembly 95, pin assembly 96 and/or mandrel assembly 97.

[0066] A second embodiment of laser level 10 is shown in FIG. 8, wherelike numerals refer to like parts. The teachings of the first embodimentabove are wholly incorporated by reference in the present embodiment.One difference from the previous embodiment is that the pendulumassembly 30 has a knife edge 36 disposed therein, which engages a notch11N in housing 11. In addition, pendulum assembly 30 may have a lowercurved area 35.

[0067] It is preferable to dispose laser assemblies 40 withinprotrusions 15 of top portion 11T. With such arrangement, when the laserlevel 10 is disposed substantially vertically against a wall, laserbeams emitted by laser assemblies 40 can exit housing 11 through windows13. As discussed above, the laser level 10 has a certain angle range,where the laser level 10 can be disposed at an angle relative to thevertical centerline V and the pendulum assembly 30 will self-level andemit substantially horizontal (or vertical) laser beams.

[0068] If the laser level 10 is disposed at an angle beyond the anglerange, laser assemblies 40 may contact the inner walls of protrusions15. Alternatively, pendulum assembly 30 may contact a component disposedwithin housing 11. When this occurs, the laser level 10 will no longerprovide an accurate leveling function.

[0069] Preferably, the windows 13 are sized to prevent the emitted laserbeams to project out of housing 11 when the laser assemblies 40 contactthe inner walls of protrusions 15 or pendulum assembly 30 contacts acomponent disposed within housing 11. This prevents the user frombelieving that the emitted laser beams are substantially horizontal (orvertical).

[0070] Preferably, the windows 13 prevent the laser beams from exitingthe housing when the pendulum assembly 30 approach the limits of theangle range. In other words, assuming an angle range being between about−10° to about 10° from vertical centerline V where pendulum assembly 30will self-level, and where the laser assemblies 40 contact the innerwalls of protrusions 15 or pendulum assembly 30 contact a componentdisposed within housing 11 at any angle beyond this angle range, it maybe preferable to size and/or shape the windows 13 to begin blocking thelaser beams at about −8° and/or about 8° from vertical centerline V.

[0071] It may be preferable to provide a pendulum lock mechanism 80 forlocking pendulum assembly 30 at a certain position. For example,pendulum assembly 30 may be locked in place in order to safely transportlaser level. Pendulum lock mechanism 80 may include a lock 84 that has alocking surface 84LR which contacts a portion of pendulum assembly 30,such as curved area 35. Lock 84 is preferably movable along its axisbetween locked and unlocked positions. A spring 86 may be trappedbetween housing 11 (via boss 11B) and lock 84 for biasing lock 84towards the locked position.

[0072] Lock 84 may be moved between the locked and unlocked positions byan actuator 83. The longitudinal axis of actuator 83 is preferablysubstantially perpendicular to the longitudinal axis of lock 84.Actuator 83 may be moved along its axis between a first position thatmoves lock 84 into the locked position and a second position that moveslock 84 into the unlocked position. Preferably, actuator 83 and lock 84have ramps 83R, 84R, respectively, for contacting therebetween.

[0073] As shown in FIG. 9, actuator 83 is shown in the first and secondpositions with solid and broken lines, respectively. As actuator 83 ismoved upwardly, ramp 83R contacts ramp 84R, and moves lock 84 towardsthe unlocked position. Actuator 83 may have a plateau 83P disposed atthe end of ramp 83R for maintain lock 84 in the unlocked position.

[0074] Actuator 83 may have an actuator button 81 to enable the user tomove the actuator 83 between the first and second positions (and thus tomove the lock 84 between the locked and unlocked positions).

[0075] Persons skilled in the art will recognize that actuator 83 may beconnected to a switch 82, so that when actuator 83 is moved, switch 82is activated. Preferably, switch 82 turns laser assemblies 40 on andoff.

[0076] Persons skilled in the art should also recognize that the spatialrelationship between actuator ramp 83R, lock ramp 84 and the traveldistance of switch 82 can be manipulated so that the switch 82 will turnon laser assemblies 40 only when lock 84 is moved to the unlockedposition. Alternatively, the spatial relationship between actuator ramp83R, lock ramp 84 and the travel distance of switch 82 can bemanipulated so that the switch 82 will turn on laser assemblies 40before lock 84 is moved to the unlocked position. This allows the userto use the laser level 10 to emit straight laser lines, even thoughthese lines are not necessarily level.

[0077] A third embodiment of laser level 100 is shown in FIG. 10, wherelike numerals refer to like parts. The teachings of the embodimentsdiscussed above are incorporated herein by reference.

[0078] Laser level 100 basically has three assemblies: base assembly110, pendulum assembly 120 and laser housing assembly 130. These threeassemblies may be designed so that they cannot be separated duringoperation. Alternatively these three assemblies may be designed so thatthey can be separated during operation and/or storage.

[0079] Base assembly 110 has a main body 111, which has a substantiallyflat rear wall to ensure that laser level 100 can be disposedsubstantially flush against a wall. Main body 111 may a central hollowcylinder 112. In addition, main body 111 may carry the stud sensorcircuit 20.

[0080] Pendulum assembly 120 preferably has a main body 121 and a hole121H on body 121 for nesting pendulum assembly 120 on cylinder 112.Preferably, main body 121 (and thus pendulum assembly 120) can rotateabout cylinder 112. Accordingly, it is preferable to dispose bearings123 therebetween to facilitate such rotation.

[0081] Main body 121 may have a compartment for receiving battery 50. Inaddition, main body 121 may have an annular protrusion 122.

[0082] Laser housing assembly 130 may have a housing 131 and at leastone laser assembly 40 disposed within the housing 131. Housing 131 mayhave a hole 131H for nesting laser housing assembly 130 onto protrusion122. Preferably housing 131 (and thus laser housing assembly 130) canrotate about protrusion 122. Accordingly, it is preferable to disposebearings 126 therebetween to facilitate such rotation.

[0083] A detent mechanism 140 may be disposed between pendulum assembly120 and laser housing assembly 130 for fixing the rotational position oflaser housing assembly 130 (and thus of laser assembly 40) relative tothe pendulum assembly 120. Detent mechanism 140 may comprise a detentball 144 which engages a notch (not shown) on housing 131. A spring 145is preferably disposed between body 121 and ball 144 to bias ball 144towards the notch. Persons skilled in the art will recognize that thespring 145 and ball 144 may alternatively be disposed on housing 131,whereas the notch can alternatively be disposed on body 121.

[0084] Preferably, the notches are disposed in such locations so thatthe laser assembly 40 will emit a laser beam that is at 90° of thevertical axis of pendulum assembly 120 (i.e., emitting a laser beamtowards the right of laser level 100, as shown in FIG. 10A), at 0° ofthe vertical axis of pendulum assembly 120 (i.e., emitting a laser beamupwardly, as shown in FIG. 10B), or at −90° of the vertical axis ofpendulum assembly 120 (i.e., emitting a laser beam towards the left oflaser level 100, as shown in FIG. 10C). Persons skilled in the art willrecognize that the notches may be disposed on other positions.

[0085] With such arrangement, the user can dispose laser level 100against a wall. The user can move laser level 100 along the wall until astud is detected by stud sensor circuit 20. While holding on to mainbody 111, the user can let pendulum assembly 120 and laser housingassembly 130 self-level, so that the emitted laser beam will besubstantially horizontal or vertical. The user can also rotate laserhousing assembly 130 to the different desired positions.

[0086] In all three embodiments, the battery 50 preferably providespower to both stud sensor circuit 20 and laser diode(s) 42, as shown inFIG. 11, so that the stud sensor circuit 20 and laser diode(s) 42operate independently from each other. Persons skilled in the art willrecognize that it may be desirable to enable the stud sensor 20 tocontrol the laser diode(s) 42, so that the laser diode(s) 42 only turnon when a stud is detected by stud sensor 20.

[0087] Another embodiment of the novel laser level is shown in FIG. 13,where like numerals refer to like parts. The teachings of theembodiments above are wholly incorporated by reference in the presentembodiment. Like before, laser level 10 has laser assemblies 40 forprojecting laser beams, preferably in the form of planes. Furthermore,laser level 10 has a stud sensor circuit 20.

[0088] In this embodiment, the main difference is that the laserassemblies 40 are not disposed on a pendulum. Instead, they are fixedlyconnected to housing 11. Accordingly, the user can disposed housing 11at any position against a wall or floor, and two laser lines will beemitted unto the wall or floor.

[0089] A horizontal bubble vial 11HV may be provided on housing 11 toindicate to the user when the laser beams are level, i.e., substantiallyhorizontal. Similarly, a vertical bubble vial 11VV may be provided onhousing 11 to indicate to the user when the laser beams are plumb, i.e.,substantially vertical. Persons skilled in the art will recognize thatother means for detecting and indicating whether the laser beams areplumb or level can be used. In addition, persons skilled in the art willrecognize that it may be preferable to dispose at least one laserassembly 40 at 90° from another laser assembly 40, to emit aperpendicular laser beam or line.

[0090] Persons skilled in the art may recognize other additions oralternatives to the means disclosed herein. However, all these additionsand/or alterations are considered to be equivalents of the presentinvention.

1. A laser level disposable on a reference surface comprising: ahousing; a pendulum pivotably connected to the housing; a first laserdiode disposed on the pendulum for emitting a first laser beam along afirst path; and a first lens disposed on the pendulum in the first pathfor converting the first laser beam into a first planar beam, the firstplanar beam forming a first line on the reference surface.
 2. The laserlevel of claim 1, further comprising a second laser diode disposed onthe pendulum for emitting a second laser beam along a second path, and asecond lens disposed on the pendulum in the second path for convertingthe second laser beam into a second planar beam, the second planar beamforming a second line on the reference surface.
 3. The laser level ofclaim 2, wherein the first and second lines are substantiallyperpendicular.
 4. The laser level of claim 2, wherein the first andsecond lines are substantially parallel.
 5. The laser level of claim 1,further comprising a detector circuit disposed in the housing fordetecting a feature behind or underneath the reference surface.
 6. Thelaser level of claim 5, wherein the detector circuit detects at leastone of the group consisting of studs, wire and pipes.
 7. The laser levelof claim 5, wherein the detector circuit controls the first laser diodeso that, upon detecting the feature, the first laser diode lights up. 8.The laser level of claim 5, wherein the detector circuit does notcontrol the first laser diode.
 9. The laser level of claim 1, furthercomprising a pendulum locking mechanism for selectively locking thependulum.
 10. The laser level of claim 1, wherein the first line issubstantially horizontal and the reference surface is a substantiallyvertical wall.
 11. The laser level of claim 1, wherein the housing atleast partially encloses the pendulum.
 12. The laser level of claim 12,wherein the housing has at least one window for allowing the firstplanar beam to exit therethrough.
 13. The laser level of claim 12,wherein the housing is configured so that the first planar beam cannotexit through the at least one window when the pendulum is at a selectedangle relative to the housing.
 14. A detection instrument disposable ona reference surface comprising: a housing; a first laser diode disposedin the housing for emitting a first laser beam along a first path; afirst lens disposed in the housing in the first path for converting thefirst laser beam into a first planar beam, the first planar beam forminga first line on the reference surface; and a detector circuit disposedin the housing for detecting a feature behind or underneath thereference surface.
 15. The detection instrument of claim 14, furthercomprising a second laser diode disposed in the housing for emitting asecond laser beam along a second path, and a second lens disposed in thehousing in the second path for converting the second laser beam into asecond planar beam, the second planar beam forming a second line on thereference surface.
 16. The detection instrument of claim 15, wherein thefirst and second lines are substantially perpendicular.
 17. Thedetection instrument of claim 15, wherein the first and second lines aresubstantially parallel.
 18. The detection instrument of claim 14,wherein the detector circuit detects at least one of the groupconsisting of studs, wire and pipes.
 19. The detection instrument ofclaim 14, wherein the detector circuit controls the first laser diode sothat, upon detecting the feature, the first laser diode lights up. 20.The detection instrument of claim 14, wherein the detector circuit doesnot control the first laser diode.
 21. A laser level disposable on areference surface comprising: a housing; a first laser diode disposed inthe housing for emitting a first laser beam along a first path; a firstlens disposed in the housing in the first path for converting the firstlaser beam into a first planar beam, the first planar beam forming afirst line on the reference surface; and at least one bubble vial on thehousing.
 22. The laser level of claim 21, further comprising a secondlaser diode disposed in the housing for emitting a second laser beamalong a second path, and a second lens disposed in the housing in thesecond path for converting the second laser beam into a second planarbeam, the second planar beam forming a second line on the referencesurface.
 23. The laser level of claim 22, wherein the first and secondlines are substantially perpendicular.
 24. The laser level of claim 22,wherein the first and second lines are substantially parallel.
 25. Thelaser level of claim 21, further comprising a detector circuit disposedin the housing for detecting a feature behind or underneath thereference surface.
 26. The laser level of claim 25, wherein the detectorcircuit detects at least one of the group consisting of studs, wire andpipes.
 27. The laser level of claim 25, wherein the detector circuitcontrols the first laser diode so that, upon detecting the feature, thefirst laser diode lights up.
 28. The laser level of claim 25, whereinthe detector circuit does not control the first laser diode.
 29. Thelaser level of claim 21, wherein the first line is substantiallyhorizontal and the reference surface is a substantially vertical wall.30. The laser level of claim 21, wherein the housing has at least onewindow for allowing the first planar beam to exit therethrough.
 31. Alaser level disposable on a reference surface comprising: a housing; afirst laser diode disposed in the housing for emitting a first laserbeam along a first path; a first lens disposed in the housing in thefirst path for converting the first laser beam into a first planar beam,the first planar beam forming a first line on the reference surface; anda hanging assembly connected to the housing for mounting the laser levelto the reference surface.
 32. The laser level of claim 31, furthercomprising a second laser diode disposed in the housing for emitting asecond laser beam along a second path, and a second lens disposed in thehousing in the second path for converting the second laser beam into asecond planar beam, the second planar beam forming a second line on thereference surface.
 33. The laser level of claim 32, wherein the firstand second lines are substantially perpendicular.
 34. The laser level ofclaim 32, wherein the first and second lines are substantially parallel.35. The laser level of claim 31, further comprising a detector circuitdisposed in the housing for detecting a feature behind or underneath thereference surface.
 36. The laser level of claim 35, wherein the detectorcircuit detects at least one of the group consisting of studs, wire andpipes.
 37. The laser level of claim 35, wherein the detector circuitcontrols the first laser diode so that, upon detecting the feature, thefirst laser diode lights up.
 38. The laser level of claim 35, whereinthe detector circuit does not control the first laser diode.
 39. Thelaser level of claim 31, wherein the first line is substantiallyhorizontal and the reference surface is a substantially vertical wall.40. The laser level of claim 31, wherein the hanger assembly comprises areference surface assembly that contacts the reference surface.
 41. Thelaser level of claim 40, further comprising a magnet disposed on one ofthe reference surface assembly and the housing, and a metal platedisposed on the other of the reference surface assembly and the housing.42. The laser level of claim 40, wherein the reference surface assemblycomprises at least one of the group consisting of a pin and a mandrel.